<?php

namespace Api\Util;
/**  
 * 常用对称加密算法类  
 * 支持密钥：64/128/256 bit（字节长度8/16/32）  
 * 支持算法：DES/AES（根据密钥长度自动匹配使用：DES:64bit AES:128/256bit）  
 * 支持模式：CBC/ECB/OFB/CFB  
 * 密文编码：base64字符串/十六进制字符串/二进制字符串流  
 * 填充方式: PKCS5Padding（DES）  
 *  
 * @author: linvo  
 * @version: 1.0.0  
 * @date: 2013/1/10  
 */   
class Xcrypt{    
   
    private $mcrypt;     //方式
    private $key;        //秘钥 
    private $mode;       //模式 
    private $iv;         //是否使用向量
    private $blocksize;    
   
    /**  
     * 构造函数  
     *  
     * @param string 密钥  
     * @param string 模式  
     * @param string 向量（"off":不使用 / "auto":自动 / 其他:指定值，长度同密钥）  
     */   
    public function __construct($key, $mode = 'cbc', $iv = "off"){  
        switch (strlen($key)){    
            case 8:    
                $this->mcrypt = MCRYPT_DES;    
                break;    
            case 16:    
                $this->mcrypt = MCRYPT_RIJNDAEL_128;    
                break;    
            case 32:    
                $this->mcrypt = MCRYPT_RIJNDAEL_256;    
                break;    
            default:    
                die("Key size must be 8/16/32");    
        }    
   
        $this->key = $key;    
   
        switch (strtolower($mode)){    
            case 'ofb':    
                $this->mode = MCRYPT_MODE_OFB;    
                if ($iv == 'off') die('OFB must give a IV'); //OFB必须有向量    
                break;    
            case 'cfb':    
                $this->mode = MCRYPT_MODE_CFB;    
                if ($iv == 'off') die('CFB must give a IV'); //CFB必须有向量    
                break;    
            case 'ecb':    
                $this->mode = MCRYPT_MODE_ECB;    
                $iv = 'off'; //ECB不需要向量    
                break;    
            case 'cbc':    
            default:    
                $this->mode = MCRYPT_MODE_CBC;    
        }    
   
        switch (strtolower($iv)){    
            case "off":    
                $this->iv = null;    
                break;    
            case "auto":    
                $source = PHP_OS=='WINNT' ? MCRYPT_RAND : MCRYPT_DEV_RANDOM;    
                $this->iv = mcrypt_create_iv(mcrypt_get_block_size($this->mcrypt, $this->mode), $source);    
                break;    
            default:    
                $this->iv = $iv;    
        }    
   
    }    
   
    /**  
     * 获取向量值  
     * @param string 向量值编码（base64/hex/bin）  
     * @return string 向量值  
     */   
    public function getIV($code = 'base64'){    
        switch ($code){    
            case 'base64':    
                $ret = base64_encode($this->iv);    
                break;    
            case 'hex':    
                $ret = bin2hex($this->iv);    
                break;    
            case 'bin':    
            default:    
                $ret = $this->iv;    
            }    
        return $ret;    
    }    
   
    /**  
     * 加密  
     * @param string 明文  
     * @param string 密文编码（base64/hex/bin）  
     * @return string 密文  
     */   
    public function encrypt($str, $code = 'base64'){    
        if ($this->mcrypt == MCRYPT_DES) $str = $this->_pkcs5Pad($str);    
   
        if (isset($this->iv)) {    
            $result = mcrypt_encrypt($this->mcrypt, $this->key, $str, $this->mode, $this->iv);      
        } else {    
            @$result = mcrypt_encrypt($this->mcrypt, $this->key, $str, $this->mode);      
        }    
   
        switch ($code){    
            case 'base64':    
                $ret = base64_encode($result);    
                break;    
            case 'hex':    
                $ret = bin2hex($result);    
                break;    
            case 'bin':    
            default:    
                $ret = $result;    
        }    
   
        return $ret;    
   
    }    
   
    /**  
     * 解密   
     * @param string 密文  
     * @param string 密文编码（base64/hex/bin）  
     * @return string 明文  
     */   
    public function decrypt($str, $code = "base64"){        
        $ret = false;    
   
        switch ($code){    
            case 'base64':    
                $str = base64_decode($str);    
                break;    
            case 'hex':    
                $str = $this->_hex2bin($str);    
                break;    
            case 'bin':    
            default:    
        }    
   
        if ($str !== false){    
            if (isset($this->iv)) {    
                $ret = mcrypt_decrypt($this->mcrypt, $this->key, $str, $this->mode, $this->iv);      
            } else {    
                @$ret = mcrypt_decrypt($this->mcrypt, $this->key, $str, $this->mode);      
            }    
            if ($this->mcrypt == MCRYPT_DES) $ret = $this->_pkcs5Unpad($ret);    
        }    
   
        return $ret;     
    }     
   
    private function _pkcs5Pad($text){    
        $this->blocksize = mcrypt_get_block_size($this->mcrypt, $this->mode);      
        $pad = $this->blocksize - (strlen($text) % $this->blocksize);    
        return $text . str_repeat(chr($pad), $pad);    
    }    
   
    private function _pkcs5Unpad($text){    
        $pad = ord($text{strlen($text) - 1});    
        if ($pad > strlen($text)) return false;    
        if (strspn($text, chr($pad), strlen($text) - $pad) != $pad) return false;    
        $ret = substr($text, 0, -1 * $pad);    
        return $ret;    
    }    
   
    private function _hex2bin($hex = false){    
        $ret = $hex !== false && preg_match('/^[0-9a-fA-F]+$/i', $hex) ? pack("H*", $hex) : false;        
        return $ret;    
    }    
   
}  